My new end-fed half-wave (EFHW) antenna consists of a 132-foot radiating wire fed via a 49:1 matching transformer. The transformer brings the impedance of the wire to 50 ohms, more or less. It’s definitely “more or less.” EFHWs are high impedance antennas and their characteristics are sensitive to their surroundings. My store-bought EFHW came with a small in-line coil six feet out from the matching transformer. That coil is there to add a small amount of inductance to lower the antenna’s resonant frequency on 10 meters. This is a tried and true approach to getting an EFHW antenna to cover […]
Continue readingHal Kennedy
Around the Shack de N4GG April, 2025
As with ham radio in general, this column has readers at all levels of technical expertise. Ohm’s law might seem basic to many, but to others it’s seldom used and in the category of “once learned then forgotten.” As a practicing EE, Ohm’s law is second nature to me. It’s one of the lenses through which I view the everyday world. I can’t see a transceiver, or a power supply, or an antenna, or power lines, or a toaster without thinking about how many amps, volts and/or watts are involved. Meanwhile, most of us are not EEs. The good news […]
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